In Macbeth, the "fatal vision" of a dagger leads on to murder and
blood-soaked revenge. Author Joe McGinniss (The Selling of the
President 1968, Going to Extremes), uses the image for his chilling
investigation of three atrocious deaths that occurred more than a
decade ago. But the use of the quote is a bit askew. The Thane of
Glamis killed for ambition; Dr. Jeffrey MacDonald, outwardly an
all-American winner, brutally murdered his wife and small daughters for
reasons that remain elusive.